[R-sig-ME] Force the random effects variances to be the same

[piuo244 m@iii@g oii @ucki@@du@i@@c@@z]

 Hi Thierry,
Because I would like to fit a heritability model, where the genetic variance should be the same for mother and father. I was doing this with lme4qtl which allows correlated random effects. In my case, the correlation matrix is a block diagonal matrix, and a block looks like
1     0   1/2 1/2 1/20     1   1/2 1/2 1/21/2 1/2 1    1/2 1/21/2 1/2 1/2 1    1/2
1/2 1/2 1/2 1/2 1

But the performance of the Laplace approximation is quite poor for binary data with small cluster sizes. I think letting nAGQ=3 might help, but lme4qtl does not allow me to do so.
Cheers,Zoe    On Friday, May 13, 2022, 07:37:07 PM GMT+12, Thierry Onkelinx <thierry.onkelinx using inbo.be> wrote:  
 
 Why would you want to do that?
ir. Thierry Onkelinx
Statisticus / Statistician
Vlaamse Overheid / Government of Flanders
INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND FOREST
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance 
thierry.onkelinx using inbo.be
Havenlaan 88 bus 73, 1000 Brussel
www.inbo.be

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Op do 12 mei 2022 om 23:29 schreef pluo244 using aucklanduni.ac.nz <pluo244 using aucklanduni.ac.nz>:

Hi,
I would like to use lme4::glmer to fit a model of the form
y ~ x + (0+m|group) + (0+f|group)

where a group looks like 
m f1 00 11/2 1/21/2 1/2
1/2 1/2

I was wondering if it is possible to force the variances of the random effects to be the same?
Many thanks,Zoe 
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